Apparatus for determining the angle of projection for projectiles from aerial vessels.



H. BOYKO-W. APPARATUS FOR DETERMINING THE ANGLE OF PROJECTION FOR PROJEGTILES PROM AERIAL VESSELS.

APPLICATION FILED SEPT 2'7; 1913.

xi /g To all whom it may concern nnrTnn snares PArnn r a ms. I

HANS BOYKOVV, OF GERMANY.

APPARATUS FOR IDETERMININGVTHE ANGLE or PROJECTION FOR PROJECTILES FROM AERI L vEssnLs. j 1

Specification of Letters Patent. P tQ t t 1 14 Application filed September 27, 1813. Serial No. 752,197.

Be it known that I, HANS BOYKOW, K. K.

Fregatten-Leutnant a. 1)., residing at 51 Esmarch street, Kiel, Germany, have invented certain new and useful Improvements in Apparatus for Determining the Angle of Projection for Projectiles from Aerial Yessels of which the following is a specification.

This invention relates to apparatus for determining the angle of projection for projectiles discharged from an aerial vessel in order to strike a given target. The projectile at the instant at which it leavesthe vessel has a horizontal velocity equal to that at which the vessel is traveling and its path is v a parabola defined by this velocity, and by the velocity of its fall which bears a definite relationship to the height of the vessel above the target. The projectile must therefore be discharged when the target is at a certain angle to the line of projection or departure of the projectile determined these two considerations, this angle beingthe angle of projection. As will be hereinafter demonstarted it is possible to discover this angle by the time occupied by the apparent movement of a fixed object on the earths surface (when viewed from the aerial vessel) through any selected angle of vision when the second factor viz.,' the height of the aerial vessel is known. This height is read from the barometer. The'time occupied by the apparent movement of a stationary object through a fixed angle was first of all determined by means of a stop watch and then by means of a table of curves the adjustment of the sighting apparatus to the required angle was effected. \Vhile the fixed object is traveling the definite angle of vision according to the present invention the adjustment of the angle is made automatically, so that immediately after this measurement the apparatus is ready for sighting the target.

In order that the said invention may be clearly understood and readily carried into effect, I will describe the same more fully with referenceto the accompanyingdrawing in which Figures 1 and 9- are diagrams explaining the theory of the lmproved apparatus. Fig.

3 is a diagrammatic representation of the essential parts of the improved apparatus. Fig.4 is a view showing the whole of the .said apparatus. Figs. 5 and 6 illustrate de-' tails and Fig. 7 shows the sub-division of the field of vision through the apparatus.

n Referring to Fig. 1, It represents the height of the aerial vessel from the ground.

.If a is the velocity or speed'of the said vessel, s the path traversed in the time t, and a the angle fromwhich the path '3 is viewed from the said vessel, then s=v.t .'.s=h.tan. a:

Consequently "0 i tan. a-

t in

i If the angle pied by the projectile in falling, B'the path traversed during this time by the airship (that is to say by the projectile also) in the horizontal direction with the velocityo, q: the angle of projection that is to be ascertained, and jectile, then This is the second equation hereinafter rei'erred to.

If the equivalent of c that has been ascertained in the first equation be inserted in the second we get 0.5774h.s e tan. gD-T 0.5 774.

But:

y g and therefore tan. q1 =0.5774. g

a 1 'constant.

ferred to.

g-the acceleration of the pro- This is the third equation heremafter reilapbikhfsiiirhg a arded apparatus consists of a device having the character of ajsexan-t (Fig- 3). Opposite-atelescope-1:

fixed amirror which is only partially -sil' vered so that, in the known, manner, a

'part. I of. the. rays of light passes right through it, while another portion is reflected onto a mirror arrangement, This arrangement-consists of two mirrors 3 and l ar ranged relatively to each other in such a manner that theyappear side by side in the field of vision through the telescope. The mirrorr3=is similar to. the mirror 2 and is fixed in such a manner that the rays II reflected by it are at anangle of to: the

'rays I'. The mirror 4 is angularly dis- ,pla'ceable'and is adjusted by means of a clock movement so that ,the' rays III re- ,flected by it makethe angle q; with the rays I. The third equation gives'the basis for the operation of the adjusting mechanism.

' [As the term t occurring in the said equation represents the time in which a sighted object onthe'earths surface'passes through the angle of 30, the'clockmovement forming part of the adjusting device "mustoperv I ate; fo-rthe'peri'od in which the object upon the earths surface appears first in IIand thenin the ray I. 4

'-F 5 shows the adjusting mechanism.

--I-t' consists,of .a carrier 5-which isdisplaceable laterally by means of a screw-6, and

fwhich carries the clock movement 7 which is started and stopped by means of a pin 8. The clock movement drivesa screw threaded spindle 9 mounted in-thecarrier 5. The ar- ,rangement. may be suchthat the pin 8 cou- I ples and uncouples a iconstantly moving part of the clock movement to and from the screwthreaded spindle 9, instead of starting and stopping the clock movement. A collar or nut 10 cotiperates with this spindle,

this not being if desired mounted in a guide luponythe nut lo engages. If the-distance spindle .9 be made equal' to i for each height h'by I. constant X fi, of the. third equation, which can be effected the lateral displace;

I ment"of the carrier 5,-and if the spindle 9 be then ja'llowed to rotate for a period-lot time If so thatthe nut 10 is displaced to an 0 the arm 12 with theaxis of the spindle. 9 is extent proportionate to t, the angle made by i equal to q) in accordance with the third equa tiOn and as shown in Fig; a

At its pivoting: point 11 the arm 12' carries agear wheel 15 which meshes with a scope.

the ray In the-second extremecase, that is to say,

gear wheel 16 having twice theknumber of teeth as that of the wheel 15. The movable mirror 43 is connected with the spindle of this latter gear whe'eh The mirror 4 is arf ranged in such ama nner that'in the position of the arm 12 illustrated it is perpen-.

.dicular to the axis of the spindle 9 and to the axis of the telescope. This is so because f t==o, tan; 71: 00 and p=Rt .allows the ray III. to issue at right angles where R is a right angle. If the arm 12 is displaced in such a manner that it makes the angle (p with the axis ofthe spindle 9, the wheel 15 is rotated through q2 and the mirror through (90 p). The ray III is deflected through twice this angle, that is to say through 90f p makes the angle-c with the axis of the tele- As already stated, the mirror 4L occupies such a position when the instrument is set' at zero that it allows the ray III- to issue perpendicularly to the axis'of the telescope and then that is to sayp'arallel to the surface of the ground, while by the rotation of the screw 9- it'is deflectedin such a manner that the I my meets the surface of the ground at an angle wh ch increases when 2? increases.

These positions are based upon the following consideration-:If -the aerial vessel should be traveling at avery high speed, the-time in whicha stretch of the earths surface visible at an angle of 30 is trav-- ersed, would be very-small.

Accordingly, 25 would be very small and the mirror would then be displaced from itsv zero position by a'very small amount. With such a high speed of the aerial vessel, however, the proje'ctile, which continues to travel withthe same horizontal velocity component would have to-be discha'rgeda long way in front of the target, (2'. e. before the vessel is vertically above-the" target) so. that the target must be sighted at the maximum angle that is to'. say, the angle ref-[projection is "at its maximum. From this it 'follows that in the zero position in which't is Zero the rayIII must make the maximum angle with-the surface of-the ground, that is to say must run parallel with it. This is in agreement with the. third equation in which I t=0,tan; p=ooand=R."

whe'n the airship is stationary so that. the

projectile has .no horizontal. displacement component it would have to be discharged vertically above'the target, and accordingly the'ray- III would have to be perpendicular to the surface of the earth.

In this case r the time t for traversing a stretch'of theearths surface appearing at an angle of I i .309 would be infiniteand the screw threaded "spindle9 would displace the arm 12 through% alright angle (assuming that both the spindle and arm "were-lofinfinite. length).

By theoscillation of the arm'l2 the-mirror 4 would be displacedlto the extent of half R and the ray HI to the extent of'R fromthe zero position, thati's to say, for the infinite magnitude t the ray II I would assume the perpendicular position-to the earths surface. '-It will, of c'ourse', be understood-that neither of these extreme cases is possible in not shownon the drawing. a

practice and that only the intermediatec'ases have to be considered 15.

"Fig.. 4 illustrates the telescope in; combination with the adjusting mechanism arranged in a casing 17 which is shown in sec-.'

' tion. Theadjusting-screw 6 and the [pin 8 protru'de"from this casing. "The scale yin accordancewith which the carrierf5 is adjusted is fixed to the casing. This scaleis order to obtain-Ythe .maximumffield *of vision it-is preferable to. employ a nonmagnifying telescope. In use the telescope must. always-be held "vertically" and-conse -quently.a level 18 is arranged upon it,'-wl1ose image'is projected by prisms and lenses into the field of vision in theknown manner.- 'Fig. -7 represents the field of vision. Its

- several zones are indicated I, II,- I'II ,-to cor}- respond with the designation of the ra s ,whenthe field ofthescrew 6. Throughout the entire duration -of thefmeasurement the instrument'is .mamtained exactly vertical in accordance with the level visible in the zone IV. At the moment at which any convenient, and plainly visible object on the earths surface in the zone II, passes through crossthreads when the telescope .is held vertical, the clock movement is started or coupled with the spindle by means of the pin 8. At the moment at v which the same object passes throughthe-cross threads in the zon I, or

with a field of vision of adequate magnitude inthe zone II also, the clock movement is stopped by means of the pin 8. The mirror .4 has then been automatically adjusted and the apparatus can immediately afterward be employed for sighting 'thetarget, the projectile being discharged as soon as the target is opposite the cross threads or the like in the zone III.

time lapsing between the measurement bf jectile is practically reduced to the mini-.

ofaim as, in actual practice, the measured mum whichjlar'ge'ly increases'thercertainty.

the angle q: and the dischargeof theproangle: is. applicable "approximately' the r time; of. measurement only}; owing .to variavessel which peatedly.-

Having thusdescribed my .invention, what 1 claim as new; and desire to secure by Letters Patent, -is:"- 9 a v l. "In apparatus for determiningthe angle. of' projection for projectilesdischarged from'an aerial vessel, adjustablefmeansfor of necessity ."take place 're-.

portion of the ea'rth?s surface q through a tomatica'lly adjusting said-sighting means,

definite angle of .v-ision,'.and meanslfor' autions thespeed andlheight of .the'aerial sighting the target,- means for -viewing a during 'the' time taken by the apparent movement of a fixedobject through the said angleof vision so that the said sighting means. are then set at the correct angleto' the line of projection of the projectile.

from an aerial vessel, adjustablezmeans' for ich oneis. only partially 'silvered, so, ar-

sighting the target, two hxed mirrors of w 2. Inapparatus for determiningth'e angle 40f projection for projectiles, discharged ranged that a portion of the earths' sur face may be viewed-through a definite angle "of visionand means for automatically adustlngisaid sightlng means ,during the time taken y the apparent movement of a fixed .thatthe said sighting. means are then set at'the correct angle tolthe line of projection of the projectile. q 3.. Inapparatus' for determining the angle of pro ect on for projectiles discharged from an aerial vessel, a fixed'mirror, an adjustable mirror, and means. for automirror di'lring" the time taken by the'a-pparent movement of a fixed objectthrough a "definlte angle of visionso thatthe said angle to the lineof projection of the'proectile.

'matically adjusting the last .mentioned 'objectthrough thejsaid angle jof-visionso adjustable mirror is then set at thecorrect 1 1.' 4. Inapparatus'for determining the an of pro ection for projectiles discharged from an aerial vessel, two fixed mirrors of .which one is only-partially silvered, so 'arranged that a portion of the earths surface can be seen through a1 definite angle of v1s1on, an adjustable'mirror, and means for automatically adjusting the-last mentioned mirror during the time taken by the apparent movement of a: fixed object through the saidangle of vision so thatthe said ad justable' mirror is then set at the correct angle to the line of projection of the-proje'ctile. E a

' By means :of'the improved apparatus the 5.;In apparatu's fordetermining the angle of projection for projectiles discharged from an" aerial vessel, two fixed mirrorsof which one is only partially silvered so arranged that a portion, of the 'earths surface can be seen through an angle of vision of thirty degrees, an adjustable mirror, and means i 'for automatically adjusting the last mentioned mirror during the time takenby the apparent movement of a fixed object through taken by the apparent movement of a fixedobject through the said angle of. vision so that the said sighting means are then set at the correct angle to the line of projection of the projectile, means for bringing said automatic adjusting means into operation when an object. enters the angle of vision and for th'rowing'it out of operation as the object leaves'the angle of vision.

- 7. In apparatus for determining the angle of projection for projectiles discharged from an aerialvessel, two fixed mirrors of which lull-14,705

one is only partially silver-ed 5 arranged that a portion of the earths surface .c'an' .be seen through a definite angle of vision, an

adjustable mirror, 2. pivoted member, means.

for connecting said member withthe said 1' adjustable mirror, means for oscillating-said member and means for varying the distance i between the -last mentioned means: and the pivotal point of said member; 1

8. In apparatus for determining the-angle of projection for projectiles discharged from an aerial vessel,.two fixedmirrors of which one is only partially silvered so arranged that a portionof the earths surface can be seen through a definite angle of vision, an

adjustable mirror, a pivoted member, gear wheels in the ratio ofone to two connecting said mirror to thesaidmember, a screw threaded spindle, means for rotatingsaid spindle, a nut on said spindle, means on said nut for engaging withthe pivoted member,

a carrier in which the screw-threaded spin I dle is mounted andmeans for efiecting movement of'said carrier toward and away from-the pivotal point of the said member.

In testimony whereofI aflix my signature in presence of two witnesses.

Witnesses:

FERDINAND RoHwIoWA, AooLr FLAMMEL.

- .II-IANS BOYKOW. i 

